Embodiments of the invention generally relate to an apparatus and a method for flowing a gas into a processing chamber. More specifically, embodiments of the invention are directed to linear flow apparatus for directing a flow of gas to a processing chamber such as an atomic layer deposition chamber or chemical vapor deposition chamber.
In the field of semiconductor processing, flat-panel display processing or other electronic device processing, vapor deposition processes have played an important role in depositing materials on substrates. As the geometries of electronic devices continue to shrink and the density of devices continues to increase, the size and aspect ratio of the features are becoming more aggressive, e.g., feature sizes of 0.07 μm and aspect ratios of 10 or greater. Accordingly, conformal deposition of materials to form these devices is becoming increasingly important.
During an atomic layer deposition (ALD) process, reactant gases are introduced into a process chamber containing a substrate. Generally, a region of a substrate is contacted with a first reactant which is adsorbed onto the substrate surface. The substrate is then contacted with a second reactant which reacts with the first reactant to form a deposited material. A purge gas may be introduced between the delivery of each reactant gas to ensure that the only reactions that occur are on the substrate surface.
Gas distribution apparatus, sometimes shaped like and referred to as showerheads, distribute processing gases to a substrate (also referred to as a wafer) at close proximity. Gas distribution apparatuses, including showerheads, have large volumes which can be very difficult to clean or purge between gases. Any gases remaining in the showerhead may react with subsequent processing gases. For ALD processes, separation of gases is important within a gas distribution apparatus, including showerheads, that relies on alternating pulses of gases, for example, an A pulse, a B pulse, an A pulse, and a B pulse type delivery. Therefore, there is an ongoing need in the art for improved gas distribution apparatuses, including showerheads, that are easy to clean/purge and provide a uniform supply of gases to the substrate.